fn band_heights(height: usize, bands: usize) -> Vec<usize>Expand description
The rows of each band a conversion of height rows splits into for up to bands threads
(convert_to_yuv_mt): height / bands floored to an even number and at least 2, the last band
taking the rest wherever fewer than a band and 2 rows would be left after it. One band where
bands <= 1 or the image fits one.